Butler D K, Metzenberg R L
Department of Physiological Chemistry, University of Wisconsin, Madison 53706.
Genetics. 1989 Aug;122(4):783-91. doi: 10.1093/genetics/122.4.783.
We have investigated the heritability of nucleolus organizer region (NOR) size in Neurospora crassa. By pulsed-field gel electrophoresis, we followed in genetic crosses the size of the normal or "terminal" NORs and the size of a small interstitial NOR. Tetrad analysis revealed that changes in NOR size occur frequently in the sexual phase. Moreover, most size changes occurred in the period between fertilization and meiosis, although some changes occurred during and after meiosis. Unexpectedly, increases and decreases in NOR size were not equally frequent: decreases were more common. The NOR size changes generated during meiosis were not the result of unequal crossing over between NORs on homologous chromosomes.
我们研究了粗糙脉孢菌核仁组织区（NOR）大小的遗传力。通过脉冲场凝胶电泳，我们在遗传杂交中追踪了正常或“末端”NOR的大小以及一个小的间质NOR的大小。四分体分析表明，NOR大小的变化在有性阶段频繁发生。此外，大多数大小变化发生在受精和减数分裂之间，尽管有些变化发生在减数分裂期间和之后。出乎意料的是，NOR大小的增加和减少并不同样频繁：减少更为常见。减数分裂期间产生的NOR大小变化不是同源染色体上NOR之间不等交换的结果。
